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> There’s no excuse.

I politely disagree. None of the programming languages which started integrating Unicode was targeting from bare metal to GUI, incl. embedded and OS development at the same time.

C++ has a great target area when compared to other programming languages. There are widely used libraries which compile correctly on PDP-11s, even if they are updated constantly.

You can't just say "I'll be just making everything Unicode aware, backwards compatibility be damned, eh".

But we don't have to make everything Unicode aware. Backward compatibility is indeed very important in C++. Like you rightly said, it still has to work for PDP-11 without breaking anything.

But the C++ overlords could always add a new type that is Unicode-aware. Converting one Unicode string to another is a purely in-memory, in-CPU operation. It does not need any I/O and it does not need any interaction with peripherals. So one can dream that such a type along with its conversion routines could be added to an updated standard library without breaking existing code that compiles correctly on PDP-11s.

> Converting one Unicode string to another is a purely in-memory, in-CPU operation.

...but it's a complex operation. This is what libICU is mostly for. You can't just look-up a single table and convert a string to another like you work on ASCII table or any other simple encoding.

Germans have their ß to S (or capital ß depending on the year), Turkish has ı/I and i/İ pairs, and tons of other languages have other rules.

Esp, this I/ı and İ/i pairs break tons of applications in very unexpected ways. I don't remember how many bugs I reported, and how many workarounds I have implemented in my systems.

Adding a type is nice, but the surrounding machinery is so big, it brings tons of work with itself. Unicode is such a complicated system, that I read that even you need two UTF-16 characters (4 bytes in total) to encode a single character. This is insane (as in complexity, I guess they have their reasons).

Thanks for the reply! Really appreciate the time you have taken to write down a thoughtful reply.

No problems! If you want a slightly longer write-up, here's a classic I constantly share with people:

https://blog.codinghorror.com/whats-wrong-with-turkey/

> Unicode is such a complicated system, that I read that even you need two UTF-16 characters (4 bytes in total) to encode a single character. This is insane (as in complexity, I guess they have their reasons).

Because there are more than 65,535 characters. That's just writing systems, not Unicode's fault. Most of the unnecessary complexity of Unicode is legacy compatibility: UTF-16 & UTF-32 are bad ideas that increase complexity, but they predate UTF-8 which actually works decently well so they get kept around for backwards compatibility. Likewise with the need for multiple normalization forms.

I mean, I already know some Unicode internals and linguistics (since I developed a language-specific compression algorithm back in the day), but I have never seen a single character requiring four bytes (and I know Emoji chaining for skin color, etc.).

So, seeing this just moved the complexity of Unicode one notch up in my head, and I respect the guys who designed and made it work. It was not whining or complaining of any sort. :)

Cuneiform codepoints are 17 bits long. If you're using UTF-16 you'll need two code units to represent a character.

you also need two UTF16 code units for plain emojis.

Lots of emoji are outside the Basic Multilingual Plane and need 4 bytes in UTf-8 and UTF-16. That's without going into skin color and other modifiers and combinations.

It's because Unicode don't allow for language switching.

It takes up to eight bytes per character in Unicode if you want to support both Chinese and Japanese in a single font using IVS(and I don't think there's any font that actually supports this).

AFAICS(As far as I can search), Simplified(PRC) and Traditional(Taiwan) Chinese encoding are respectively called GB2312 and Big5, and they're both two byte encodings with good practical coverage. Same applies for Japanese Shift_JIS. If e.g. :flag_cc: were allowed to be used as start-of-language marker, one could theoretically cut that back down to two bytes per character without losing much and actually improving language supports.

The number of characters is not the problem, the mess due to legacy compatibility is - case folding and normaltization could be much simpler if the codepoints were laid out with that in mind. Also the fact the Unicode can't make up its mind if it wants to encode glyphs (turkish I and i, han unification) or semantic characters (e.g. cyrillic vs. latin letters) or just "ideas" (emojis).

> Germans have their ß to S (or capital ß depending on the year)

FYI, it's never S. If there is no better option then SS and ss are the proper capital and lowercase substitutions.

Java ended up picking UCS-2 and getting screwed.

Pretty much all Unicode early adopters went for 16-bit chars. Qt and Win32 API are another pair.

Indeed, ICU as well, and then they all moved to UTF-16, which, again. in the long term lost to UTF-8. My point is that committing on a specific Unicode design 30 years ago was not, in retrospect, necessarily a good idea.

By not committing to UCS-2 early C++ left the road open to UTF-8. I'll concede that UTF8 has risen as the clear winner for more than a decade and C++ is well past the point that it should have at least basic builtin support. The problem is that there is at least one important C++ platform that only very recently added full support for the encoding in their native API.

Qt really has no excuse for still using 16-bit characters since unlike the other two they have had multiple ABI breaks since then.

"no excuse" -- I would respectfully disagree here. There are lots of very smart people who have worked on Qt. Really, some insanely good C++ programmers have worked on that project. I have no doubt that they have discussed changing class QString to use UTF-8 internally. To be clear, probably QChar would also need to change, or a new class (QChar8?) would be needed, in parallel to QChar. I guess they concluded the API breakage would be too severe. I assume Java and Win32/DotNet decided the same. Finally, you can Google for old mailing list discussions about QString using UTF-16. Many before have asked "can we just change to UTF-8?".

Ah yes, appeal to authority. No better way to admit that you are talking out of your arse.

Java was built from scratch as a heavy language with a whole portability layer that C++ does not have. Also, libraries have been around to do this stuff in C++ but maybe some people saw it better to not require C++ to support Unicode, presumably.

Java has 16-bit character types. It is in no way better at modern Unicode than C++ while being needlessly less efficient for mostly-ASCII text like XML-like markup.

> There’s no excuse.

Until mid-2000s there was no certainty Unicode will eventually defeat competitors. In real it havenʼt fully yet - GB2312 and Tron are still locally prevailing, and IBM still jogs with EBCDIC. But at its early times nobody was reasonably sure, and Java attempt could have failed as well. (More so Java approach for UCS-2 was wrong - already commented nearby.)

Java embraced Unicode, and ended up with a mess as Unicode changed underneath it.

You can actually end up in a cleaner state in C++, as there is no obligation to use the standard library string classes, but it's pretty much required in Java.